One of the hallmarks of growing older is the realisation that as this occurs, time gradually seems to go by faster. When we were children starting to school in September, the nine-month-long school year seemed an eternity. It was a time span so vast we could hardly comprehend it. By the time we were seniors in high school, the months were zipping by - "Time flies when you're having fun." Then, faced by four eternal years of college, time seemed once more to crawl. But once we enter the working world, we encounter the strangest of all paradoxes relative to time - how slowly the hours and days pass; yet how rapidly the weeks go by. As we grow older and more experienced in our jobs, the hours still seem to pass slowly yet the months and years whiz by. But it's only after retirement that the pace really picks up. Then, hours, days, weeks, months, years, entire decades all pass by so quickly we are aghast to realise we may very well have lived three-fourths, maybe even four-fifths of our lives already.

Paralleling this realisation, we see the transient nature of life appearing quite often in the work of older artists. It almost never appears in the work of artists under thirty. Moreover, it's rare in the work of those under fifty. But from that point on, it's often a recurring theme. And, except for overt references such as seen in Dutch vanitas still-lifes, more often than not, the competing forces of time and nature have been seen in landscape painting. Sometimes they're referred to as allegorical landscapes, though there's always the risk of reading more into a work of this kind than the artist may have intended.

Perhaps one of the earliest paintings of this type came from the Dutch artist, Jacob van Ruisdael, his The Jewish Cemetery, painted around 1655-60. He was around 30 at the time, which might seem rather young for such profound visual contemplation, but keep in mind he died at the age of 52. (Life was short and not necessarily sweet in the seventeenth century.) In his painting, a rainbow promises relief from a stormy sky as the clouds part and an unseen sun briefly illuminates a ruined cathedral, which forms a backdrop for the mausoleums of the cemetery. Nearby flows a "stream of life" passing by the long dead. A recently downed tree bridges the stream (possibly symbolising a passing from death into an afterlife) while in the foreground is the gnarled trunk of living tree jutting upward - nature in defiance of the passing storm of life.

In such landscape paintings, trees are often used metaphorically with reference to man. They spring from a single trunk but are supported by a multitude of roots while splaying out, as they grow taller and older. It's no accident that genealogy utilises the tree in its graphic depictions of human ancestry. A tree is a living, breathing, growing thing, more permanent than the flowers, but less so than the rocks and soil from which it springs. These are the eternal elements, often depicted in the form of mountains, as in Thomas Coles's View of Schroon Mountain, Essex County New York, After a Storm (1838). It's an autumn scene, brilliant in colour, but transient in nature as the trees exalt in a last gasp of radiance while the storm affects all but the pyramidal top of the mountain rising above it. To the far left is a trunk, apparently blasted by wind or lightning, while nearby, two others, beaten and bruised by age, nonetheless struggle on against the elements. Cole was 37 when he painted Schroon Mountain. He lived to be 47.

Around the same time, Caspar David Friedrich, the ethereal German landscape painter, depicted an aged figure dressed in traditional German garb paying homage to a prehistoric tomb. A misty, wintry sun, low in the sky, illuminates a lavender early evening and the naked limbs and branches of his allegorical trees attempt to defy the elements of life arrayed against them. The figure, like the trees, seems to be hovering between life and death. It is an intensely emotional dialog between man and nature, adjudicated by time. Friedrich was about 60 years old when he painted A Walk at Dusk. He died in 1840 at the age of 66.

Today, as we look upon our living room walls, we don't so often see the transience of life reflected in landscape painting (or other genres either, for that matter). I suppose it's not something we want to think about as we sit night after night watching TV, while blissfully ignoring the hours as they tick by. Yet it's not an uncommon theme every weekday afternoon on television. "Like sand through the hourglass, so are the days of our lives."